Loop Powered Ultrasonic Flow Measurement

Loop-powered measurement devices have increased in popularity in the recent past because of
the simplicity of their installation. A single cable to the flow meter carries both power to the
meter and flow information back to the control system. New low-powered ultrasonic transducer
technology, coupled with smart-microprocessor power management, allow the GE Panametrics
AquaTrans UTX878 ultrasonic flow meter to function as a loop-powered meter.

Transit-Time Flow Measurement Technique

The Correlation Transit-Time™ technique uses a pair of transducers with each transducer
sending and receiving coded ultrasonic signals through the fluid. When the fluid is flowing, signal
transit-time in the downstream direction is shorter than in the upstream direction; the difference
between these transit-times is proportional to the flow velocity. The AquaTrans UTX878 measures
the time difference and uses programmed pipe parameters to determine flow rate and direction.